The present invention relates to a fuel injection apparatus for diesel engines, which is capable of assuring stable operation of a diesel engine even when the diesel engine is operated in a skip-cylinder mode.
In the prior art, in order to control the output from a multi-cylinder diesel engine, the diesel engine is often operated in so-called skip-cylinder mode in which fuel is supplied from a fuel injection pump to only particular cylinders selected in accordance with the operating condition of the engine. As disclosed in, for example, Japanese Patent Application Disclosure Nos. Sho 56-106,055 and Sho 57-38,629, the skip-cylinder operation of an engine is carried out by selectively cutting off the fuel supply to one or more cylinders selected in accordance with the operating condition of the engine.
However, since the operating condition of the engine changes when it is changed to skip-cylinder mode, various disadvantages arise. For example, when skip-cylinder operation is carried out so as to supply fuel to half of the cylinders of the engine, the change in output torque increases and the period thereof becomes double. Furthermore, the time period between the time the adjustment of the position of the member for adjusting the amount of fuel injection is carried out and the time the injected fuel starts to burn also becomes double, so that the control delay time becomes double. As a result, in skip-cylinder mode of engine operation, hunting is liable to occur and engine vibration is apt to increase, so that it becomes difficult to operate the engine stably.